In leafy London suburbia, Mike and Christine (Butcher and Blake) are settling down for a tense dinner when their doorbell rings. Three of their son Sebastian's friends (Hunter, Chin and Muslim) barge in and say they'll wait for him to get home. But things take a horrific turn as it becomes clear that these drug-addled guys are furious with Sebastian. Tired of waiting, they take Mike and Christine hostage and start taking out their anger on them.

Williams is a smart, inventive filmmaker (see London to Brighton), using lush cinematography and a rich colour palette to build a quiet sense of menace. The opening moments have a zing of realistic marital intensity, which is underscored by TV reports of violence and death, plus dialog peppered with raw wit and dark irony. But most of this subtlety evaporates with the sudden home invasion, and the rest of the film is basically an experiment in grisly paranoia.

There are bigger themes here, such as the clash between this well-off white couple and the poorer ethnic kids who assault their ordered life. The two sides are as frightened as each other, but the kids happen to have weapons as well as the advantages of their youth and their increasing numbers. This is about bravado and control, not intelligence (no one has a plan). But Williams never develops any nuance that would add resonance to the brutality: this is just how it is.

At least it's eerily believable, played with force by a cast of relative unknowns who sound like they're improvising the dialog. This gives the scenes an unpredictability that makes the film watchable. And the events play out over real time, with gives the film a real kick, especially as Mike and Christine are forced into uncharacteristic action. Williams keeps most violence off-camera, knowing that sounds freak us out more effectively. But without any depth, it feels rather vacuous and exploitative, preying on our suburban fears for a quick thrill. Except that it's not very scary. It's just vicious and nasty.

At high school, the popular teens cruelly taunt the outcasts over an upcoming costume party that's due to be the coolest event of the year. But the party is actually part of a plan by the nerds to get even for years of bullying. Led by the unpredictable Dane (Donato), they're heavily armed and extremely well-prepared. And before they know what hit them, the cool kids are tied up and seemingly in one of those Saw movies, facing unspeakable torture at the hands of the people they have tormented.

Slickly produced, the film is directed to skilfully build suspense even before anything happens. The plot grows subtly, steadily, drawing us into the characters' turmoil, both the thoughtless mean kids and the desperate outcasts. There isn't much complexity here, though, despite a few broad strokes in the script that try to hint at subtext or moral dilemmas. Basically this is a wish-fulfilment fantasy for anyone who was picked on for being outside the inner circle in high school.

After the cursory set-up, the film quickly descends into an orgy of rather unoriginal viciousness. Since the victims have now become monsters, there's no one left to sympathise with. The main problem is that these supposedly smart, sensitive geeks are both ruthless and rather unimaginative; clearly they haven't really thought through their plan, as they supposedly only intended to scare and scar their oppressors, but their methods are much deadlier than that. And everything predictably spirals out of control.

As this night of terror progresses, there's little for the actors to do with their characters besides adopting the posture of a horror movie stereotype. And while the cheesy script strains to reference both Columbine and Vietnam, it's far too contrived for that. If there's any consolation, at least director Stewart cuts away from (or botches) most of the brutality. Although that will annoy genre fans, as will the fact that it's never actually scary.

Lindsay and Jenny (Williams and Yennie) are naive Americans driving through Germany when they get lost on the way to a nightclub. Disoriented in the woods, they find the home of Dr Heiter (Laser), who quickly drugs them so he can use them for an experiment he previously tried on his dogs, namely sewing them together with a third victim (Kitamura) into a three-part "centipede". Lindsay wriggles out of her bonds before the operation, but can she escape? And what will Heiter do to the cops (Leupold and Blankenstein) who come snooping around?

Frankly, the mad doctor's experiment is so hideously unthinkable that only a screenwriter would come up with it. Six claims that it's all perfectly plausible from a medical standpoint, but that doesn't make it any less horrific. Just the idea makes us feel queasy, so we can be thankful that, despite a few yucky cutaways, he leaves much of the real horror in our minds. Which makes it even more repugnant.

But it's also a stylishly made movie packed with dark humour. Six's direction is sleek and understated, quietly building suspense even if the film is never really scary. It is, however, stomach-churning. If the concept isn't vile enough, the expert make-up and costumes continually hint at graphic grisliness. While the icy filming style contrasts cleverly with the believably terrified performances from the three victims. And the camp, over-the-top Laser is thoroughly creepy.

The main problem, of course, is that it seems to have no real point. The film feels like the Hostel movies, poking fun at dumb tourists who fall into the clutches of sadistic psychopaths. Or maybe it's a jab at how we let scientists indulge in all kinds of experimentation without properly questioning it. Whatever it is, at least it too engaging to be called torture porn. And it certainly marks Six as a filmmaker to watch. After he makes Part 2, that is.

Shane (Kwanten) is a young city cop who has just arrived in the small Australian town of Red Hill with his pregnant wife (van der Bloom). And his first day on the job turns out to be rather momentous. First, his new boss (Bisley) and a grumpy officer (Sutherland) give him difficult jobs to do. Then a ruthless killer (Lewis) escapes from prison and heads straight to Red Hill. Yes, Shane's first day descends into mad chaos. And there's clearly "something else" going on here.

So far so good, and filmmaker Hughes builds a palpable sense of menace as the plot develops. On the other hand, he also drops in early references to a wild panther and an approaching mega-storm, signposting everything so heavily that it's difficult to be surprised by what happens along the way, however random it seems. And the solid central narrative begins to get shoved aside by all of these arbitrary and pointless plot elements.

Kwanten holds the film together very nicely as the city-slicker forced to overcome his past in order to move forward. His wrenching fear resonates strongly, as does his resolve to protect his wife and get to the bottom of an increasingly dangerous situation that's feeling shadier by the moment. As he does in True Blood, he brings a terrific sense of physicality to the role, throwing himself into the action scenes in a way that's thoroughly believable.

Even as Hughes keeps the tone low-key and steady, he pushes every element far over-the-top. It's like he doesn't trust the central character and main plot to hold our interest, so he continually distracts us by filling scenes with extraneous hyperbole. For example, the killer is more like a comic book villain than a real person, and his story plays out in an interesting way that's unnecessarily preachy and sentimental. But we never really doubt how it'll all end. The bigger question is when that panther will turn up.